For nearly a year, Eileen M. Rehrmann has been flying just below the radar of most Maryland voters.

Her uphill battle to steal the Democratic nomination from Gov. Parris N. Glendening this September has been waged in low-key campaign stops -- a Hagerstown Rotary Club luncheon, a Gaithersburg crafts fair -- not on the front pages or prime time TV.

That could change soon. Recent days have brought strong suggestions that two top Democrats, Baltimore Mayor Kurt L. Schmoke and Prince George's County Executive Wayne K. Curry, may split with Glendening and possibly -- possibly -- come out in support of Rehrmann after the General Assembly adjourns today. Both men are close allies of her campaign manager, Larry S. Gibson, one of Maryland's most influential political operatives, who says that the governor he helped elect can no longer beat the likely Republican nominee, Ellen R. Sauerbrey.

Such backing would provide immediate credibility for the little-known Harford county executive, whose campaign thus far has centered less on who she is than on the fact that she's not Glendening or Sauerbrey.

"People say, 'I'm not voting for him, I don't want to vote for her. I'm glad you're in the race,' " Rehrmann said.

A youthful-looking 53-year-old described as "schoolmarmish" by Baltimore Magazine, Rehrmann, a former teacher, shares former college professor Glendening's dry and deliberate manner, as well as similar stands on many issues.

She cites combative Sen. Barbara A. Mikulski (D-Md.) as a political role model -- "She's a fighter for what she believes in." Yet Rehrmann is undeniably more conservative, winning strong support from business leaders for her austere budget policies.

"You have to understand that people work hard for their paychecks," Rehrmann said in a recent interview. "You have to be careful how you spend it."

Two years ago, few would have figured her as the type to make a public split with her party's incumbent: Rehrmann's plan was to run for state comptroller after serving the maximum eight years as Harford county executive. She stepped up to the governor's race only after Comptroller Louis L. Goldstein -- 85 and considered unbeatable -- made the surprise decision to seek his 11th term this year.

But Rehrmann insists that it was genuine disappointment with Glendening that inspired her to enter a race once contemplated but later passed up by more prominent Democrats such as state House Speaker Casper R. Taylor Jr. and Rep. Benjamin L. Cardin.

"People don't believe they can count on" Glendening, she said, ticking off a list of complaints: that the former Prince George's county executive actually left behind a projected budget deficit after boasting of a surplus in his last year; that he secured plush pensions for top aides; that he committed $200 million to build a football stadium to lure the Cleveland Browns to Baltimore; and that he flip-flopped in withdrawing support for a long-planned road in the D.C. suburbs.

In particular, Rehrmann blasts Glendening's support last year for $254 million in extra financial aid to Baltimore schools over five years, which she describes as a political giveaway that spurred other jurisdictions -- including her own -- to clamor for equal treatment.

"Our children's education shouldn't be based on whether you voted for the governor," she said.

Tim Phillips, Glendening's campaign manager, dismissed such claims, noting that the state economy is booming and crime is down. "This governor has been good for the state," he said, adding that Rehrmann has no "positive message of her own."

Rehrmann, a native of the Philadelphia suburbs, attended Immaculata College and taught for three years before moving in 1966 to Harford County, where she and her husband -- a chemist from whom she is now separated -- raised their four children. Like many women of her generation, she entered politics through interest in her own children's education, climbing the ranks of the PTA before winning a seat on the Bel Air Town Council in 1978.

Elected to the House of Delegates in 1982, Rehrmann was appointed to the Appropriations Committee, where colleagues remember her work with then-Gov. William Donald Schaefer (D) on a plan to improve operations at the struggling port of Baltimore.

Returning to Harford County, the Democratic legislator was twice elected county executive by voters who also elected an entirely Republican County Council in 1994. Occasionally criticized for an autocratic style, she is largely praised by her Republican colleagues for teamwork and cooperation.

"She is very strong-willed," said Del. James M. Harkins, a Harford Republican who is running for county executive this year. "But also, when she sends something [to Annapolis] and we disagree with it, she has at least come and met with us."

Rehrmann boasts of her success in pulling the county through the severe recession that hit in 1991 -- without cutting services, raising property tax rates or hurting the county's impressive bond rating. Others note that the rural-suburban county (population 204,000 -- about the size of Howard County, and growing almost as fast) entered the recession in strong fiscal shape, and that Rehrmann's job was made easier by the modest expectations of a conservative community.

The suburban gubernatorial hopeful got a surprising boost when Gibson joined her campaign last fall. A Baltimore lawyer best known for masterminding the campaigns of black politicians such as Schmoke and Curry, Gibson helped turn out the inner-city vote that pushed Glendening over the edge in his narrow 1994 victory over Sauerbrey.

Some party activists say Gibson split with Glendening over the governor's opposition to allowing slot machines at Maryland racetracks, for whom Gibson does legal work. While not taking a strong stand on the issue, Rehrmann has left the door open to slots.

Gibson, though, says he was disillusioned by Glendening's failure to deliver promised state aid to Baltimore for its circuit courts, police and a summer jobs program. The governor denies breaking commitments to the city, and his defenders say he has showered record amounts of school aid on the city.

Rehrmann is trying to be more than just an anti-Glendening candidate. In stump speeches, she promises a "bill of rights" for HMO patients and says Maryland should consider opening a maximum-security facility for young criminals, offering education and counseling.

The flashiest promise in Rehrmann's platform is a call to eliminate the state property tax -- 21 cents per $100 of assessed value -- which generates about $240 million a year. Although Glendening and leading senators dismiss the idea as a gimmick, it has received support from House Speaker Taylor.

Yet many political insiders say the strongest argument for Rehrmann is simply that she is not Glendening.

"What she brings is sort of a fresh beginning in terms of character-type issues," said Jerry Pasternak, the top political adviser to Montgomery County Executive Douglas M. Duncan (D) and one of several party activists helping Rehrmann. "Democrats dread the notion of an Ellen Sauerbrey victory, and many are looking for an alternative."

Others note that while the governor's shaky approval ratings once boded well for Rehrmann, her chances clouded when former Washington Redskin and insurance executive Ray Schoenke -- who says he will spend at least $2 million of his own fortune -- joined the Democratic race. Many think Rehrmann, Schoenke and fellow challenger Terry McGuire are doomed to split the anti-Glendening vote. Some suggest that Rehrmann's only effect will be to weaken the governor for the general election.

"If the objective is to knock [Glendening] off in the primary, I don't see it happening," said pollster Del Ali. "All they do is take away from each other."